emulib.emustudio.debugtable.OpcodeColumn Maven / Gradle / Ivy

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/*
 * KISS, YAGNI, DRY
 *
 * (c) Copyright 2006-2017, Peter Jakubčo
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package emulib.emustudio.debugtable;

import emulib.plugins.cpu.AbstractDebugColumn;
import emulib.plugins.cpu.Disassembler;
import emulib.runtime.exceptions.InvalidInstructionException;

import java.util.Objects;

/**
 * This class represents "opcode" column in the debug table.
 *
 * The opcode means operating code - the formatted binary representation of the instruction.
 */
public class OpcodeColumn extends AbstractDebugColumn {
    private final Disassembler disassembler;

    public OpcodeColumn(Disassembler disassembler) {
        super("opcode", String.class, false);
        this.disassembler = Objects.requireNonNull(disassembler);
    }

    /**
     * Has no effect.
     *
     * @param location memory address (not row in debug table)
     * @param value  new value of the cell
     */
    @Override
    public void setDebugValue(int location, Object value) {
    }

    /**
     * Get opcode for an instruction at specific location.
     *
     * @param location  memory address (not row in debug table)
     * @return String containing the opcode of an instruction at specific location
     */
    @Override
    public Object getDebugValue(int location) {
        try {
            return disassembler.disassemble(location).getOpCode();
        } catch (InvalidInstructionException | IndexOutOfBoundsException e) {
            return "";
        }
    }

    @Override
    public int getDefaultWidth() {
        return -1;
    }

}